Anyone know if it is possible to add a 2nd air conditioner in a 2017 Greyhawk 29ME? Mine can't keep up with the heat over 90 degrees!

You're not alone. It's unbearable in our 2016 31FK.

Here's a recap of what I think our options are:
- one person here popped off the Fantastic Fan in the back and dropped on a 13.5K Soft Start AC unit
- they're pleased with the results
- but fishing the 120V AC line was a chore and performed by their RV tech
- someone else asked Jayco about it and Jayco said "No! That section of the roof is not reinforced like it is on newer models"
- you'll still have to be careful not to overload the circuits on gen or shore power. (Ie. don't have both AC units running and start the microwave)

Here's what I'm trying first. I'm running a test of it as we speak.

I popped onto Craislist and picked up a lightly used Portable AC unit. Paid about $100

Our 2017 Redhawk had the rear vent framed for a second AC unit but no power. Someone on the forum recently had Jayco confirm that the 2017 units and up are framed for the second AC.

I added a 13.5k power saver unit and ran a second 15amp circuit. There is a power outlet in the cargo area that I can plug the 2nd AC into while on generator power and can run both ACs as long as I don't turn much else on.

We've had it installed about 18 months and covered probably 3/4k plus miles and it works great.

It was an option, but it would have also included the power management system to allow both to run together.They would have been 2 13,500 units.

With that said the wiring may already be in the roof. Remove the rear vent trim ring to see if the wire is there. You will need to install the power management controls if you do add it.

Grumpy...we have the two airs and they are both 11,000 units. You are correct that with the power management system installed with the second air option they both run together fine on 30amp service. If something else is turned on like microwave then the management system will shed the rear air until the power comes back then the second air kicks back in.

Both airs are ducted together which really helps move the air throughout the coach. I was a little worried that they weren't but 11,000 units but with both running it really does a good job.

You lose the heatpump option with two airs so I am limited to propane heat only. I use ceramic space heaters most of the time unless it gets real cold.

Maybe a option for the ones who need more a/c would be to get a larger single unit. I think a 15,000 would fit same space as a 13,500. Not sure that would be enough help.

I once read from another web page where they installed a 10k unit and ran a shielded exterior cable. He stated although he had to modify the exterior wall mounted receptacle, and uses a external drop cord to the power pole. He only uses the second unit 10% of the camping experience.

Anyone know if it is possible to add a 2nd air conditioner in a 2017 Greyhawk 29ME? Mine can't keep up with the heat over 90 degrees!

Yes. I did it through a dealer with the blessing and instruction of Jayco. I installed two 11,000 BTU units, just as Jayco does for their option (I have a 2017 GreyHawk 29W and the option came out just after I took delivery of my unit). The coach was prewired and already had the Energy Management System preinstalled from the factory.
I live in AZ and they work together exceptionally well. The 15000 BTU unit with the heat pump that came with the coach was absolutely worthless in anything above 85 degrees !! Losing the heat pump was no concern because, even in freezing temperatures, the gas unit does the job easily. It is not a cheap conversion, but well worth the expense. Otherwise, the MH would be in hibernation each summer, rendered useless.